Synergistic mixtures of selected amino acids

ABSTRACT

Novel synergistic fungicidal compositions used for protecting seeds, plants and other vegetative material against fungi contain a mixture of one or more compounds selected from group A and one or more compounds selected from group B. Compounds from group A are selected from β-Amino butyric acid and its N-benzoyl-octyl ester derivatives. Compounds from group B are selected from the group of fosetyl aluminum, dimethomorph, a mixture of folpet and ofurace (45:5), folpet, fencaramid (Bayer SZX), mancozeb, cymoxanil, methalaxyl, the single optical isomer of metalaxyl, a mixture of cymoxamil and mancozeb (4:1), copper sulfate, copper hydroxide, copper sulfate hydrate, azoxystrobin, and acibenzolar-s-methyl.

INTRODUCTION

[0001] The present invention concerns synergistic fungicidal mixtures. The present invention more particularly concerns synergistic mixture of β-aminobutyric acid (hereinafter referred to as BABA) and its N-benzoyl-octyl ester derivatives for the control of plant diseases.

BACKGROUND OF THE INVENTION

[0002] Fungicides are often combined in mixtures for 3 main reasons: 1. to widen the spectrum of antifungal activity to control several diseases occurring simultaneously in a crop 2. to exploit synergistic interaction between fungicides, by which the overall activity is increased and the concentration of the compounds reduced, and 3. to delay the selection process of resistant fungal individuals to one component of the mixture (Gisi, Phytopathology 86 1273-1279,1996).

[0003] Avoidence of plant disease in agricultural production may be accomplished not only by using fungicides or fungicidal mixtures but also by using “plant activators”, molecules which enhance the natural resistance (defense) of the plant. Such activators which have no direct fungicidal effect on the pathogen (Ryals et al The Plant Cell 8: 1809-1819,1996), induce systemic acquired resistance (SAR) in the plant several days after application (Ibid).

[0004] To date only few molecules were reported to induce SAR in crop plants viz. salicylic acid (SA), 2,6-dichloroisonicotinic acid (INA) benzol (1,2,3) thiadiazole-7-carbothiouic acid S-methyl ester (BTH) (Ibid), and DL-3-amino butyric acid (BABA, Cohen et al Plant Physiology 104: 56-59,1994).

[0005] However whereas SA, INA or BTH have to be applied to the crop ahead of infestation (Ryals, et al Ibid) BABA can be applied post-infectionaly (Cohen et al Ibid).

[0006] The idea behind the present invention is to combine two methods of disease control—the direct-kill method operating on the target pathogen and the indirect method of activating the natural defense approach of the crop plant. Such two methods are combined by using mixtures of a fungicide or fungicides (direct-kill) with BABA or its N-benzoyl-octyl ester derivative (SAR).

[0007] We show here that such mixtures are synergistic in controlling plant diseases.

OBJECTIVES OF THE INVENTION

[0008] It is the objective of the present invention to provide novel mixtures of fungicides of β-aminobutyric acids. It is an objective of the present invention to provide a synergistic mixture of BABA and/or its N-benzoyl-octyl ester derivative with various other fungicides.

SUMMARY OF THE INVENTION

[0009] In accordance with the present invention there is provided synergistic fungicidal compositions comprising one or more compounds selected from Group A and one or more compounds selected from Group B, wherein the compounds of Group A are selected from the group consisting of DL-3 aminobutyric-acid and its N-Benzoyl octyl ester, and the compounds of Group B are selected from the group consisting of fosetyl aluminum, dimethomorph, a mixture of folpet and ofurace (45:5), folpet, fenearamid (Bayer SZX), mancozeb, cymoxanil, methalaxyl, the single optical isomer of metalaxyl, a mixture of cymoxamil and mancozeb (4:1), copper sulfate, copper hydroxide, copper sulfate hydrate, azoxystrobin, and acibenzolar-s-methyl.

[0010] The present invention also provides an improved method of controlling fungi, especially late blight and downy mildews, applying to the plant a composition containing an effective amount of one of these mixtures. The present invention further provides an improved method of controlling phytophthora infertan in potato or tomatoe, Pseudoperonospora cubensis in cucumber or melon, Plasmopera viticola in grapes, and Peronospora tabacina in tabacco.

DETAILED DESCRIPTION OF THE INVENTION

[0011] Methodology

[0012] Plants

[0013] 1. Potato (cultivar Alpha) were grown from tubers in 1 liter pots in sandy soil in the greenhouse. At 5 weeks after planting when they had several shoots in a pot, with 10-12 leaves per shoot, plants were taken for assays.

[0014] 2. Cucumber (cultivate Dlila) plants were grown from seed in 0.251 liter pots containing sandy soil in the greenhouse. At 3 weeks after sowing, when they developed 2 leaves they were used.

[0015] 3. Grapes (cultivate Superior) plants were grown from cuttings (first in perlite and then tin sandy soil) in pots in the greenhouse. At 8 weeks after planting leaves were detached for experiments.

[0016] Fungal Pathogens.

[0017] Potatoes were inoculated with sporangic of Phytophthora infestans (resistant to metalaxyl). Cucumbers were inoculated with sporangia of Pseudoperonospora cubensis (resistance to metalaxyl). Grapes were inoculated with Plasmopara viticola.

[0018] Chemicals.

[0019] 1. DLPβ-amino-butanoic acid (BABA)

[0020] 2. DL-4-benzoyl-3-amino butanoic acid octylester (039-81)

[0021] 3. Cymoxanil (Curzate)

[0022] 4. phosetyl-aluminium (Alliette)

[0023] 5. Mancozeb

[0024] 6. Folpet

[0025] 7. Metalaxyl, metalaxyl-Gold

[0026] 8. Copper sulphate, copper hydroxide

[0027] 9. (Mancozeb+dimethomorph, prepacked 600 g+90 g a.i.per 1 kg)

[0028] 10. (Mancozeb+metalaxyl, prepacked 560 g+75 g a.i. per 1 kg)

[0029] 11. Folpet+ofurace, 450 g+60 g a.i. per 1 kg)

[0030] 12. Bayer-SZX (Fencaramid)

[0031] 13. Mancozeb+Cymoxanil (4:1)

[0032] 14. Azoxystrobin

[0033] 15. Acibenzolar-s-methyl

[0034] 16. Dimethomorph

[0035] Except BABA which was dissolved in water, all other chemicals or prepacked mixtures produced a suspension or emulsion in water.

[0036] Spraying

[0037] The chemicals were sprayed onto the upper leaf surfaces of either potatoes or cucumbers with the aid of a fine glass atomizer. Control plants were sprayed with water. Experiments with grapes were carried out using 12 mm leaf discs floating on 1 ml of the test compound(s) in 24-well titer plates, upperside down.

[0038] Inoculation

[0039] Potatoes and cucumbers were inoculated one day after spraying. Grape leaf discs were inoculated soon after floating.

[0040] Inoculation of potato was done by spraying the upper leaf surfaces of the plants with a sporangial suspension containing 2000 sporangia/ml. Sporangia were harvested 0.5 h before inoculation from infected potato tuber slices. Cucumbers were sprayed with a sporangial suspension containing 1500 sporangia/mi. Sporangia were harvested from infected cucumber plants kept in humid growth chambers (at 15° C.). Leaf discs of grapes were inoculated with 2 sporangial droplets containing each 300 sporangia. Sporangia were harvested from infected leaves kept in petri dishes on wet filter paper at 15° C. Inoculated plants or titer plates were placed in a dew chamber at 18° C. overnight and then transferred to a growth chamber at 20° C. (12 h light/day 100 pE.m⁻².S⁻¹) for symptom production (late blight in potato and downy mildew in cucumber), or for sporulation of P. viticola in grape leaf discs.

[0041] General Procedure for Tabacco

[0042] One month old tobacco plants (cv.xanthi nc.). were sprayed onto their foliage with the test compounds. Two days later they were inoculated with 10⁴ spores/ml of Perouospora latacin of either the S or the R strain. Inoculated plants were placed in 100% relative humidity over night and then incubated at 20° C. with 12 h light/day. A week after innoculation plants were again placed at 100%-RH at 18° C. in the dark to induce fungal sporulation. Sporulation was quantitated by removing 2 cm² leaf discs from each leaf and counting with the aid of a haemocytometer. The extent of sporulation inhibition was calculated relative to that in control (untreated) inoculated plants. Ed_(go) was computed after linear regression and of was calculated according to Wadely.

[0043] General Procedure for Grapes

[0044] Leaf discs (2-cm²) were removed from the top leaves of grape plants (cv. Superior) grown in the greenhouse. Discs were floated (lower surface uppermost on the test solutions over filter paper of 9 cm diameter). Petri dishes. Leaf discs were immediately innoculated with 2 (10 ml) droplets of sporangial suspension (10⁴/ml) of Plasmopara viticola per disc. Dishes were inculoated at 20° C. with 12 h light/day for 10 days until fungal sporulation was quantified.

[0045] Disease Assessment

[0046] At the time intervals post inoculation specified in the Examples, infected leaf area in potato and cucumber was assessed visually. In control inoculated plants most or all of the foliage (80-100%) was devastated by the disease. Percentage control of the disease by a chemical treatment was calculated as

% control=(1−x/y)×100

[0047] whereas x=proportion leaf area diseased in treated plants

[0048] and y=proportion leaf area diseased in control plants.

[0049] In grapes, proportion of leaf discs showing sporulation were similarly used.

[0050] Calculation of Control Efficacy and Synergism

[0051] Each chemical and each mixture was applied to plants at various doses of the active ingredient. Dose-response curves were produced and transferred to log-dose probit response curves as described by Kosman and Cohen (Phytopatholagy 86: 1263-1272, 1996). ED₉₀ values (dose required for achieving 90% control of the disease) taken from the log-probit 7 curves were used to calculate the Cotoxicity Factor (CF) according to the Wadely procedure (Kosman and Cohen, Ibid; Gisi phytopatcology 86: 1273-1279,1966). “CF” is defined as the ratio between the expected dose and the observed dose that provide the same level of disease control (Kosman and Cohen, Ibid). The observed dose of each component of a mixture is taken from the experiment and the expected dose of all mixture made of that components is calculated by the Wadely formula: ${{ED}_{90}\quad {expected}} = \frac{a + b}{\frac{a}{{ED}_{90}\quad {obs}\text{.}A} + \frac{b}{{ED}_{90}\quad {obs}\text{.}B}}$

[0052] where a and b are the absolute amounts of the components A and B in a mixture and ED₉₀. obs.A and Ed₉₀ obs.B are the ED₉₀ values of A and B obtained by the experiment. CF values of >2.0 are considered to represent a strongly synergistic mixture (Gisi, Ibid).

[0053] According to a further feature of the invention, there is provided a fungicidal composition which comprises a compound of the invention together with carrier. The active compound can be employed as a wide variety of formulations, for example as an aqueous dispersion, a dispersible powder, as seed dressing, granules or dust. As a dispersion the composition comprises an active compound together with a dispersing agent dispersed in a liquid medium, preferably water. It can be in a form of a concentrated primary composition which requires dilution with a suitable quantity of water or other diluent before application. Such primary compositions are a convenient way of supplying the consumer and preferred example is a dispersible powder. A dispersible powder comprises an active compound, a dispersing agent and solid carrier. The latter can be, for example, kaolin, talc, or diatomaceous earth and in addition, the dispersible powder can contain a wetting agent.

[0054] Other formulations include seed dressing, granules or dusts, in all of which the active compound is associated with a solid carrier and which are intended for direct application. They can be made by methods well known in the art. Preferably all compositions comprising a solid carrier are made by mixing the active compound in particulate form with a particulate carrier.

[0055] The concentration of the active compound in the composition of the invention can vary widely. In the case of a, primary composition it is preferably from 15% to 95% by weight, more especially from 50% to 80% by weight. A composition intended for direct application to a crop preferably comprises from 0.001% to 10% more, especially from 0,005% to 5% by weight of the active compound, although the aerial spraying of a crop is contemplated compositions having higher concentrations, for example up to 30% by weight may be chosen in preference.

[0056] The fungicidal composition of the present invention may be applied as a ready-mixed composition, as a tank mix, or applying the compounds of each group separately.

[0057] Following the methods outlined above numerous mixtures were prepared and their activity against a variety of diseases were studied. The results of 35 studies are listed in Tables 1-35.

[0058] While the invention will now be described in connection with certain preferred embodiments in the following examples it will be understood that it is not intended to limit the invention to these particular embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as be included within the scope of the invention, as defined by the appended claims. Thus, the following examples which iclude preferred embodiments, will serve to illustrate the practice of this invention, it being understood that the particulars shown are by way of example and for purposes of illustrative discussion of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of procedures as well as of the principles and conceptual aspects of the invention. TABLE 1 CONTROL OF LATE BLIGHT IN POTATO BY BABA COPPER SULFATE HYDRATE MIXTURE^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 2 8 32 125 250 1000 mg/L CF BABA — — — 0 0 0 13 2678 — Cu⁺² — 0 0 63 83 — — 143 BABA + Cu⁺² 80 + 20 0 0 13 88 — — 126 4.7 70 + 30 0 0 50 93 — — 101 4.2 60 + 40 0 0 85 93 — — 85 3.9

[0059] TABLE 2 CONTROL OF LATE BLIGHT IN POTATO BY BABA CYMOXANIL MIXTURE (CURZATE^(R))^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 3 24 18 64 1498 — Cymoxanil — 36 73 64 98 128 — BABA + 80 + 20 9 9 3 79 — 294 1.6 Cymoxanil 50 + 50 73 76 82 98 — 114 2.1

[0060] TABLE 3 CONTROL OF LATE BLIGHT IN POTATO BY BABA FOSETYL ALUMINUM MIXTURE^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Comounds Ratio 16 62 250 1000 mg/L CF Cultivar Cara^(b) BABA 9 9 9 24 3233 — Fosetyl − Al 9 24 24 70 1390 — BABA + 75 + 25 9 9 39 70 1311 1.9 Fosetyl − Al 25 + 75 9 9 39 79 1142 1.4 Cultivar Draga^(c) BABA 0 0 0 53 1533 — Fosetyl − Al 33 33 50 93 856 — BABA + 75 + 25 67 67 93 93 639 1.7 Fosetyl − Al 25 + 75 0 0 93 100 245 3.9

[0061] TABLE 4 CONTROL OF LATE BLIGHT IN POTATO BY BABA MIXTURES OF MANCOZEB + DIMETHOMORPH MIXTURES^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — — 3 24 18 64 1498 — MANCOZEB + — 70 73 82 98 — 115 — DIMETHOMORPH BABA + 80 + 20 64 73 70 82 — 287 1.5 (MANCOZEB^(C) + 50 + 50 85 70 70 91 — 189 1.1 DIMETHOMORPH)

[0062] TABLE 5 CONTROL OF LATE BLIGHT IN POTATO BY BABA FOLPET/OFURACE (45 + 5) MIXTURE^(a) Percent Disease Control^(b) @ mg/L Active Ingredient - ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 14 14 14 36 2617 FOLPET/ 77 89 99 100 — 19 OFURACE BABA + (FOLPET/ 50 + 50 74 81 99 100 — 22 1.8 OFURCE)

[0063] TABLE 6 CONTROL OF LATE BLIGHT IN POTATO BY BABA FOLPET - CYMOXANIL MIXTURE^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 16 62 250 1000 mg/L CF BABA 22 22 22 69 1481 FOLPET 81 95 98 100 84 CYMOXANIL 83 86 91 100 183 BABA + FOLPET 60 + 25 + 15 72 89 98 100 95 2.5 + CYMOXANIL 25 + 60 + 15 92 86 95 100 104 1.3

[0064] TABLE 7 CONTROL OF LATE BLIGHT IN POTATO BY THE N - BENZOYL OCTYL ESTER OF BABA AND FENCARAMID^(a) Percent Disease Control Com- mg/L Active Ingredient^(b) ED₉₀ pounds Ratio 2 8 32 125 250 1000 2000 mg/L CF BABA — — — 15 25 50 53 2395 Deriv- ative Fenc- 0 50 98 100 — — — 19 aramid BABA DERI- 80 + 20 44 63 85 100 — — — 31 3.0 VAT- IVE + FENC- 90 + 10 13 50 56 94 — — — 97 1.8 ARA- MID

[0065] TABLE 8 CONTROL OF LATE BLIGHT IN POTATO BY N-BENZOYL OCTYL ESTER OF BABA, Cu (OH)₂, (as 50% a.i), MANCOZEB^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF N-benzoyl octyl — 3 25 25 75 1261 ester derivative of BABA Cu(OH)₂ 0 0 13 75 — 298 Cu(OH)₂ + 70 + 30 0 3 44 50 — 416 Mancozeb

[0066] TABLE 9 CONTROL OF LATE BLIGHT IN POTATO BY N-BENZOYL OCTYL ESTER DERIVATIVE OF FOLPET/OFURACE (45 + 5) AND THEIR MIXTURES^(a) Percent Disease Control @ mg/L Active Ingredient^(b) ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF N-benzoyl octyl — 0 0 0 25 2011 ester derivative of BABA Folpet + 0 0 3 73 — 301 Ofurace (9 + 1) N-benzoyl octyl

[0067] TABLE 10 CONTROL OF LATE BLIGHT IN POTATO BY N-BENZOYL OCTYL ESTER DERIVATIVE OF BABA, AND MANCOZEB + CYMOXANIL; 4:1 AND THEIR MIXTURES^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF N-benzoyl octyl — 0 0 0 25 2011 ester derivative of BABA Mancozeb + 0 25 25 75 — 313 Cymoxanil N-benzoyl octyl 67:33 25 68 70 95 — 169 4.3 ester derivative 50:50 5 63 88 98 — 95 5.7

[0068] TABLE 11 CONTROL OF LATE BLIGHT IN POTATO BY N-BENZOYL OCTYL ESTER DERIVATIVE OF BABA, FOLPET AND THEIR MIXTURES^(a) Percent Disease Control^(b) Com- mg/L Active Ingredient ED₉₀ pounds Ratio 4 16 62 250 500 1000 2000 mg/L CF N- 1514 benzoyl octyl ester — — — 63 69 85 89 deriv- ative of BABA Folpet 70 75 90 95 — — — 141 N- 80 + 20 50 80 85 93 — — — 167 3.1 benzoyl 67 + 33 13 76 86 96 — — — 130 2.8 octyl 33 + 67 63 76 78 88 — — — 224 0.9 ester 33 + 67 63 76 78 88 — — — 224 0.9 deriv- ative of BA- BA + Folpet

[0069] TABLE 12 CONTROL OF LATE BLIGHT IN POTATO BY N-BENZOYL OCTYL ESTER DERIVATIVE OF BABA, FENCARAMID (BAYER SZX) AND THEIR MIXTURES^(a) Percent Disease Control^(b) Com- mg/L Active Ingredient ED₉₀ pounds Ratio 2 8 31 25 500 1000 2000 mg/L CF N- — benzoyl octyl ester — — — 15 25 50 53 3204 deriv- ative of BABA Fenc- 0 50 98 100 — — — 19 — aramid — N- 90:10 13 50 56 94 — — — 83 2.2 benzoyl 80:20 44 63 85 100 — — — 31 3.0 octyl ester deriv- ative of BABA + Fenc- armid

[0070] TABLE 13 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, COPPER SULPHATE HYDRATE (EXPRESSED AS mg/L Cu⁺⁺) AND THEIR MIXTURES^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 16 62 250 1000 mg/L CF BABA 43 43 57 72 1468 Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 2 8 32 125 mg/L CF Cu⁺⁺ 57 72 80 89 105 BABA + Cu⁺⁺ 80 + 20 72 72 86 89 102 4.0

[0071] TABLE 14 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, (EXPRESSED AS Cu(OH)₂) (Cu(OH)₂ + MANCOZEB) AND THEIR MIXTURES Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 33 33 50 67 1576 Cu(OH)₂ 67 67 77 80 — 304 Cu(OH)₂ + mancozeb 70 + 30 67 67 83 93 — 174

[0072] TABLE 15 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA (FOLPET/OFURACE 45 + 5) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 0 29 57 71 1273 — Vamin 43 57 71 91 — 206 — BABA + Vamin 67 + 33 14 21 57 97 — 166 2.8 50 + 50 14 43 71 89 217 2.1 33 + 67 29 57 74 89 214 1.3

[0073] TABLE 16 CONTROL OF DOWNY MILDEW CUCUMBER BY BABA AND (MANCOZEB + CYMOXANIL; 4:1) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 0 29 57 71 1273 — (Mancozeb + 14 80 97 100 33 — Cymoxanil) BABA + 67 + 33 21 57 77 97 — 135 0.7 (Mancozeb + 50+:50 57 74 100 100 — 20 3.2 Cymoxanil) 33+:67 29 94 100 100 — 14 3.5

[0074] TABLE 17 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA + (MANCOZEB + METALAXYL) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 0 15 3 59 1443 — Mancozeb + Metalaxyl 34 53 71 82 — 268 — BABA + Mancozeb + 88 + 12 0 0 9 96 — 221 4.3 Metalaxyl 75 + 25 18 44 53 81 — 281 2.4 50 + 50 38 76 76 96 — 150 3.0

[0075] TABLE 18 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, FOLPET & METALAXYL^(a) 87:13) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/LF CF BABA — 0 15 3 59 1443 — Folpet & Metalaxy 0 0 56 76 — 280 — (87 + 13) BABA + [Folpet + 88 + 12 12 0 59 81 — 260 3.7 metalaxyl] 75 + 25 68 53 56 71 — 393 1.8 50 + 50 0 38 62 68 — 339 1.4

[0076] TABLE 19 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA; FOLPET & METALAXYL^(a), (7 + 1) (MANCOZEB + METALAXYL), (FOLPET + OFURACE) AND THEIR MIXTURES Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 12 19 25 31 3218 Folpet + metalaxyl 62 82 90 97 — 112

[0077] TABLE 20 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, METALAXYL SINGLE ISOMER MANCOZEB AND THEIR MIXTURES^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 8 8 8 38 2155 mancozeb 0 8 23 72 — 315 Metalaxyl Single 0 0 0 8 — 844 Isomer BABA + 55 + 40 + 5  23 23 54 75 — 313 2.0 mancozeb + 50 + 40 + 10 38 25 31 80 314 2.0 Metalaxyl 40 + 40 + 20 8 15 8 31 689 0.9 Single Isomer 45 + 50 + 5  8 8 54 72 309 1.7 40 + 50 + 10 8 31 54 89 228 2.3 30 + 50 + 10 8 15 31 83 273 1.9 35 + 60 + 5  54 54 78 86 239 2.0 30 + 60 + 10 46 38 54 85 268 1.7 20 + 60 + 20 61 69 69 83 281 1.6 25 + 70 + 5  38 46 78 97 139 3.0 20 + 70 + 10 38 23 63 94 194 2.1 10 + 70 + 20 38 69 23 78 362 1.1

[0078] TABLE 21 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, ALIETTE, CYMOXANIL AND THEIR MIXTURES Percent Disease Control^(a) mg/L Active Ingredient ED₉₀ Compounds Ratio 16 62 250 1000 mg/L CF BABA 37 67 76 85 975 — Aliette 45 85 98 99 245 — Cymoxanil 0 20 58 72 1229 — BABA + Aliette + 60 + 25 + 15 63 70 88 95 584 1.0 Cymoxanil 25 + 60 + 15 70 85 98 100 100 3.4

[0079] TABLE 22 CONTROL OF DOWNEY MILDEW IN CUCUMBER BY BABA, MANCOZEB, CYMOXANIL AND THEIR MIXTURES Percent Disease Control^(a) mg/L Active Ingredient ED₉₀ Compounds Ratio 4 16 62 250 1000 mg/L CF BABA — 0 13 50 63 1413 — Mancozeb 75 87 90 92 — 167 — Cymoxanil 13 25 38 50 — 506 — BABA + Manco- 60 + 25 + 15 63 75 83 95 152 3.0 zeb + Cymoxanil 25 + 60 + 15 75 87 90 95 136 1.8

[0080] TABLE 23 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, BAYER SZX (FENCARAMID) AND THEIR MIXTURES Percent Disease Control^(b) Com- @mg/L Active Ingredient ED₉₀ pounds Ratio 2 8 31 125 500 1000 2000 mg/L CF BABA 61 72 74 2354 FENC- 78 83 95 100 19 ARA- MID BABA+ 80 + 20 38 58 83 100 33 2.8 FENC- 50 + 50 60 80 98 100 14 2.7 ARA- 20 + 80 78 85 98 100 13 1.8 MID

[0081] TABLE 24 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, BAYER DIMETHOMORPH (DMN)AND THEIR MIXTURES Percent Disease Control^(b) Compounds Ratio @ mg/L Active Ingredient BABA 1000 gave 17% Control DMN 5 ppm gave 32% Control BABA + DMN gave 74% Control 1000 + 5 ppm $\begin{matrix} {{{Synergy}\quad {ratio}} = \frac{74 = 74}{17 = {32 - \frac{\left( {17\quad 32} \right)\quad 33}{100}}}} \\ {= 2.24} \end{matrix}\quad$

[0082] TABLE 25 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA, FOLPET, CYMOXANIL AND THEIR MIXTURES^(a) Percent Disease Control^(b mg/L) @Active Ingredient ED₉₀ Compounds Ratio 16 62 250 1000 mg/L CF BABA 6 22 48 82 1072 FOLPET 43 84 95 97 403 48 63 82 97 524 BABA + FOLPET + CYMOXANIL 25+60+15 76 87 95 99 247 2.0

[0083] TABLE 26 CONTROL OF DOWNY MILDEW IN CUCUMBER BY BABA PHOSETYL-ALUMINIUM AND THEIR MIXTURES^(a) Percent Disease Control^(b) mg/L Active Ingredient ED₉₀ Compounds Ratio 16 62 250 1000 mg/L CF BABA 10 43 43 71 1386 — Phosetyl-Aluminium 71 71 94 86 638 — BABA + 12+88 43 43 86 100 261 4.7 Phosetyl-Aluminium 25+75 0 14 71 97 551 1.9 50 + 50 0 14 57 83 1009 0.9 75 + 25 — 57 57 86 918 0.8 88 + 12 14 29 71 86 931 0.7

[0084] TABLE 27 CONTROL OF LATE BLIGHT IN POTATO BY BABA, BION AND THEIR MIXTURES^(a) Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 250 500 1000 mg/L CF BABA 38 75 93 776 — BION 13 25 78 1173 — BABA + 38 78 98 639 1.3 ACIBENZOLAR -S-METHYL (10 + 1)

[0085] TABLE 28 CONTROL OF LATE BLIGHT IN TOBACCO BY BABA AZOXYSTROBINE MIXTURE AND THEIR MIXTURES, FUNGAL ISOLATE = R Percent Disease Control ED₉₀ mg/L Active Ingredient Ratio Compounds (w/w) 5 10 25 50 100 200 mg/L CF BABA — — — 0 13 100 171 AZOXY- 13 81 81 81 93 — — 27 STROBINE BABA+ AZOXY- STROBINE 5 + 1 25 100 100 100 41 2.2 10 + 1 38 81 100 100 54 2.1 15 + 1 50 81 100 100 53 2.4

[0086] TABLE 29 CONTROL OF DOWNY MILDEW IN TOBACCO BY BABA, ACIBENZOLAR-S-METHYL, RIDOMIL-GOLD AND THEIR MIXTURES: Fungal isolate = R Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 16 62 250 mg/L CF BABA — 3 27 51 406 BION — 76 76 99 88 RIDOMILGOLD — 49 37 58 416 BABA + 75 + 1 48 78 99 90 3.1 ACIBENZOLAR-S- METHYL 10 + 1 45 93 100 52 5.9 15 + 1 22 84 91 186 1.8 20 + 1 14 74 98 116 3.5 BABA + RIDOMIL GOLD 7.5 + 1  27 63 97 150 2.7 10 + 1 34 44 99 145 2.8 15 + 1 23 52 78 282 1.4 20 + 1 0 20 91 239 1.4 BABA + 7.5 + 1 + 1  37 63 95 174 1.7 ACIBENZOLAR-S- METHYL + RIDOMIL-GOLD 10 + 1 + 1 45 71 92 190 1.7 15 + 1 + 1 37 84 82 230 1.5 20 + 1 + 1 57 98 98 84 4.2

[0087] TABLE 30 CONTROL OF DOWNY MILDEW IN TOBACCO BY BABA, ACIBENZOLAR-S-METHYL, CURZATE RIDOMIL-GOLD AND THEIR MIXTURES: Fungal isolate = R Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 100 200 400 mg/L CF BABA — 37 62 100 270 — ACIBENZOLAR — 37 50 80 443 — -S-METHYL CURZATE — 25 25 62 596 — RIDOMILGOLD 20 35 42 >1000 — BABA + 10 + 1 62 100 100 113 2.5 ACIBENZOLAR -S-METHYL 15 + 1 50 100 100 118 2.3 BABA + CURZATE 10 + 1 62 100 100 113 2.5  5 + 1 37 62 100 270 1.1

[0088] TABLE 31 CONTROL OF DOWNY MILDEW IN TOBACCO BY BABA, ACIBENZOLAR-S-METHYL, RIDOMIL-GOLD AND THEIR MIXTURES: Fungal isolate = S Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 0.5 5 50 mg/L CF BABA — 0 27 59 78 — ACIBENZOLAR — 54 76 85 52 — -S-METHYL RIDOMILGOLD 100 100 100 0.2 — BABA + 7.5 + 1 85 85 99 15 4.9 ACIBENZOLAR-S- METHYL 10 + 1 86 94 100 4 18.7 15 + 1 75 84 100 5 15.1 BABA + 7.5 + 1 94 100 100 0.5 3.3 RIDOMIL-GOLD 10 + 1 99 100 100 0.4 5.4 15 + 1 88 90 100 4.3 2.1 BABA + 7.5 + 1 + 1  99 100 100 0.4 4.4 ACIBENZOLAR-S- METHYL + RIDOMIL-GOLD 10 + 1 + 1 100 100 100 0.2 12.2 15 + 1 + 1 73 100 100 0.6 5.3

[0089] TABLE 32 CONTROL OF DOWNY MILDEW IN GRAPES BY BABA ACIBENZOLAR-S-METHYL AND THEIR MIXTURES IN LEAF DISCS Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 0.31 1.25 5 20 50 100 mg/L CF BABA — —  15  93 95 99 38   — ACIBENZOLA 0 27 75 100 — —  6 — R-S-METHYL BABA + 10 + 1  0 37  68 100 — —  6.6  3.9 ACIBENZOLA R-S-METHYL 15 + 1 60 82 100 100 — —  1.4 19.8

[0090] TABLE 33 CONTROL OF DOWNY MILDEW IN GRAPES BY BABA, ALLIETTE AND THEIR MIXTURES IN LEAF DISCS Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 1.25 2.5 5 10 20 50 mg/L CF BABA — 38 44 81 86 92 33 — ALLIETTE 13 36 38 40 48 81 — 24 BABA + ALLIETTE 1 + 1 44 81 87 89 92 — 12 2.3 3 + 1 44 69 88 92 95 — 10 3.0 5 + 1 25 31 43 47 83 — 22 1.4 7 + 1 24 31 34 56 62 — 30 1.0 9 + 1 22 34 39 55 61 — 31 1.0

[0091] TABLE 34 CONTROL OF DOWNY MILDEW IN GRAPES BY BABA, CURZATE AND THEIR MIXTURES, IN LEAF DISCS Percent Disease Control mg/L Active Ingredient ED₉₀ Compounds Ratio (w/w) 1.25 2.5 5 10 20 50 mg/L CF BABA — — 25 36 78 83 91 36 — CURZATE 11 39 58 66 55 — 27 — BABA + CURZATE 1 + 1 51 61 68 81 89 — 16 1.9 3 + 1 62 70 77 86 93 — 13 2.6 5 + 1 69 74 81 89 95 — 11 3.1 7 + 1 49 68 74 78 89 — 16 2.2 9 + 1 21 39 58 73 82 — 17 2.1 

What is claimed is:
 1. A synergistic fungicidal composition comprising synergistically effective respective amounts of (1) D,L-3-aminobutyric acid or the n-octyl ester thereof, together with (2) folpet or a mixture of folpet and ofurace.
 2. The fungicidal composition in accordance with claim 1 wherein the (1) D,L-3-aminobutyric acid or n-octyl ester thereof and the (2) folpet or mixture of folpet and ofurace are present in a weight ratio of 9:1 to 1:9.
 3. The composition of claim 2 wherein said weight ratio is 4:1 to 1:4.
 4. The fungicidal composition of claim 1 wherein fungicidal components consist essentially of (1) said D,L-3-aminobutyric acid or n-octyl ester thereof and (2) said folpet.
 5. The fungicidal composition of claim 1 wherein fungicidal components consist essentially of (1) said D,L-3-aminobutyric acid or n-octyl ester thereof and (2) said mixture of folpet and ofurace.
 6. The fungicidal composition according to claim 5 wherein the ratio of folpet to ofurace is approximately 45:5.
 7. A method of administering a fungicidal composition in accordance with claim 1 to a plant infested with a fungus, wherein the fungus is selected from the group consisting of Phytophthora infestans, Pseudopersonspora Cubensis, Plasmopara veticola, and Peronospora tabacina.
 8. A method in accordance with claim 7 wherein the fungus is selected from the group consisting of Phytophthora infestans in potatoes and tomatoes, Pseudoperonspora cubensis in cucumber and melons, Plasmopara veticola in grapes, and Peronospora tabacina in tobacco.
 9. A method of controlling fungal infections in plants comprising applying to the plants or parts thereof a synergistic fungicidal composition comprising synergistically effective respective amounts of (1) D,L-3-aminobutyric acid or the n-octyl ester thereof, and (2) folpet or a mixture of folpet and ofurace.
 10. A method in accordance with claim 9 which comprises applying said (1) D,L-3-aminobutyric acid or n-octyl ester thereof and (2) said folpet or mixture of folpet and ofurace in a weight ratio of 9:1 to 1:9.
 11. The method of claim 10 wherein said weight ratio is 4:1 to 1:4.
 12. A method in accordance with claim 9 wherein the plants are selected from the group consisting of potatoes, tomatoes, cucumbers, melons, grape vines, and tobacco.
 13. A method according to claim 9 wherein the fungus is selected from the group consisting of Phytophthora infestans, Pseudopersonspora cubensis, Plasmopara veticola, and Peronospora tabacina.
 14. A method in accordance with claim 13 wherein the fungus is selected from the group consisting of Phytophthora infestans in potatoes and tomatoes, Pseudopersonspora cubensis in cucumber and melons, Plasmopara veticola in grapes, and Peronospora tabacina in tobacco. 